Effects of P70 S6 kinase on the ageing process and reproduction of Daphnia pulex (Branchiopoda, Anomopoda)

Daphnia pulex is a natural food widely used in aquaculture, and S6K plays an important role in protein translation and ageing. To explore the function of S6K in the ageing process of D. pulex, we cloned and analysed the full-length cDNA of S6K. With the growth of D. pulex, the expression of S6K mRNA first increased, then peaked at 10 days, and then decreased. Western blot analysis showed that the S6K protein expression increased from 1 to 5 days of age, but did not change significantly from 5 to 25 days of age. RNAi knockdown of S6K, reduced the expression of S6K mRNA and S6K protein, and it causes changes in other genes associated with ageing in both sexes. S6K may be involved in reproductive transformation, affecting reproductive capacity, thus significantly affecting the ageing of D. pulex. miRNA with potential regulation of the S6K gene were screened by the bioinformatics method and validated using a dual luciferase reporter gene system. This study deepens our understanding of the mechanisms of ageing in D. pulex and expands our understanding of the role of S6K in the ageing process.